Joystick Ball-Joint Spring Balancing for Low-Wear Rotation

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Solution Overview

Problem

Existing joysticks experience high wear due to excessive friction between the bearing faces of the articulation, which is not effectively mitigated by current designs.

Innovation Solution

The joystick incorporates a mechanism with a ball joint articulation and a dual set of springs that maintain a clearance between the bearing faces, reducing friction by balancing forces and moments to return the handle to its neutral position, thereby minimizing contact between the bearing faces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the bearing faces are designed to permit rotational movement through shape-shape interaction, then the handle can rotate smoothly between neutral and inclined positions, but friction between the bearing faces increases causing excessive wear

Engineering Contradiction:

Improvesmooth rotational movementVSAvoidwear of articulation components

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A set of springs is introduced as an intermediary element between the male and female articulation portions. These springs apply a separating force that creates clearance between the bearing faces, reducing direct contact and friction while still allowing the handle to rotate smoothly through the articulation mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The springs provide beforehand cushioning by maintaining a controlled clearance between the bearing faces before contact occurs. This preventive measure reduces friction and wear by ensuring that the bearing faces do not remain in constant contact, yet the handle can still pivot smoothly when needed.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Stability of the object's composition

If the bearing faces are kept in contact to support the handle, then the handle remains stable, but friction increases causing wear

Engineering Contradiction:

Improvehandle stabilityVSAvoidwear of articulation components

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The articulation system transitions from a static contact state to a dynamic state where the bearing faces alternate between contact and separation. The springs enable this dynamic behavior, allowing the faces to separate during rotation to reduce friction, then come together to provide stability when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If a single set of springs is used to return the handle to neutral position, then the structure is simple, but the friction between bearing faces is not effectively reduced

Engineering Contradiction:

Improvespring mechanism structureVSAvoidwear of articulation components

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The spring mechanism is segmented into multiple springs arranged in a specific configuration around the articulation point. This segmentation allows the springs to collectively apply a separating force that creates clearance between the bearing faces, effectively reducing friction while maintaining structural organization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple springs are introduced as intermediary elements that collectively apply a separating force between the male and female articulation portions. This multi-spring configuration enhances the clearance effect and friction reduction compared to a single spring, while maintaining reasonable structural complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design significantly reduces friction and wear between the articulation components, enhancing the longevity and functionality of the joystick while allowing smooth rotational movement.

Implementation Method 1

a first set of springs that is interposed between the fixed body and the upper face of the rim, this first set of springs comprising one or more springs that are uniformly distributed around a vertical axis

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

exert, on the handle, in its inclined position, a mechanical moment that urges the handle toward its neutral position

Methodology Applied

Scientific EffectMechanical moment: Torque

Implementation Method 3

these bearing faces being shaped to permit, via shape-shape interaction when they rub against each other, a rotational movement of the handle

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11409321B2Joystick

Publication Date: 2022.08.09 CROUZET AUTOMATISMES SA

AI summary

A joystick comprises an articulation comprising bearing faces that are shaped to permit, via shape-shape interaction when they rub against each other, a rotational movement of a handle. A first set of springs exerts, on the handle, a first vertical force that pushes the bearing faces against each other. A second set of springs exerts, on the handle, a second vertical force in the opposite direction to the first vertical force and the amplitude of which is between 0.9|F1| and 1.1|F1|, wherein |F1| is the amplitude of the first vertical force. The first and second sets of springs are able, in the absence of external stress on the handle, to maintain a non-zero clearance between all the bearing faces of the articulation.